The present invention relates to coronary anastomosis procedures, and in particular, it relates to minimally invasive coronary anastomosis procedures.
Coronary arterial diseases remain one of the leading causes of mortality. The disease may be manifested by insufficient blood flow resulting in angina, myocardial infarction and death.
A number of approaches have been developed and used for treating coronary arterial diseases. Pharmaceuticals and lifestyle changes are used in less severe cases to lessen the progression of the disease. Coronary blockage in more severe cases is often treated endovascularly using techniques such as balloon angioplasty, atheroectomy, laser ablation, stents and hot tip probes.
In cases where the above-mentioned treatments have failed or will not likely result in reducing or eliminating the blockage, often times a coronary artery bypass graft procedure is performed using the traditional open surgical techniques. Typically, using such a technique, the patient's sternum is opened and the chest is spread apart to provide the surgeon access to the heart. A source of arterial blood is then connected to the coronary artery distal to the occlusion. Typically the heart is stopped using potassium cardioplegia and perfusion to the vital organs is supported by cardiopulmonary bypass. The source of arterial blood is often the left or right internal mammary artery (IMA).
This traditional approach is effective in relieving angina and restoring blood flow to the heart, however cardiopulmonary bypass being non-pulsatile in nature has been associated with neurophysiological disorders, stroke, renal failure, and liver disfunction. Patients typically spend two to three months recuperating before returning to work. Often times the patient cannot even drive for four to six weeks after such surgery since their chests have been severely opened.
One of the problems in performing coronary surgery is providing the surgeon sufficient access to the surgical area. Human anatomy provides the coronary area protection through the sternum, the rib cage and the costal cartilages. However, the same protective structure provides a barrier and a problem for the surgeon in performing coronary surgery. In the past, surgeons have simply cut through the sternum or the rib cage to provide access into the thoracic cavity. Sawing or cutting such structure has obvious traumatic effects on the patient.
Less traumatic procedures have been developed recently. For example, the Sterman et al. U.S. Pat. No. 5,452,733 describes a thoracoscopic coronary artery bypass procedure. This procedure uses several trocar sheaths such as used in conventional laporascopic procedures to provide access into the patient's chest and to provide access for a viewing scope. However, the bypass procedure is utilizing cardioplegia to arrest the heart and cardiopulmonary bypass to perfuse the vital organs prior to connecting the arterial graft to the coronary artery.
Similarly, the Sterman et al. U.S. Pat. No. 5,571,215 describes a method and devices for performing less-invasive arterial surgical procedures. A scope is positioned through a percutaneous intercostal penetration in the patient's chest to provide a view within the patient's chest. Through another percutaneous penetration in an intercostal space in the patient's chest, a tool is inserted to perform the surgical procedure. Again, prior to the percutaneous penetrations, the patient's heart is arrested and placed on cardiopulmonary bypass.
A number of devices have been developed for retracting bones and tissue in cardiovascular surgery. Such devices are described in the Santilli et al. Re. No. 34,150, Couetil U.S. Pat. No. 4,809,985, Chaux U.S. Pat. No. 4,852,552, Farley U.S. Pat. No. 4,989,587 and Bugge U.S. Pat. No. 5,025,779. Other devices similar in construction but useful for different surgical procedures are also disclosed in the Coker U.S. Pat. No. 5,363,841, Grieshaber U.S. Pat. No. 4,813,401, the Casper et al. U.S. Pat. No. 4,616,635, the Jascalvich U.S. Pat. No. 3,701,783 and the Nelson U.S. Pat. No. 2,670,732.
Another minimally invasive coronary bypass procedure is described in an article in the Minneapolis Star and Tribune dated Sep. 19, 1995 which describes a procedure titled "Trap Door Procedure" for performing a bypass operation in which the heart is not placed under cardiopulmonary bypass. The entry into the chest cavity is a three-inch-long opening in the lower breast bone. The heartbeat is reduced to 35 beats per minute through the use of pharmaceuticals. The IMA is clamped and is dissected for use as the bypass to restore blood flow to the heart. The blocked coronary artery is clamped and a slit is made into the artery distal to the occlusion. The IMA is sutured to the blocked coronary artery over the slice. Eight sutures are made between heartbeats and left loose until all sutures are in place. The sutures are then pulled tight and tied to close the two arteries together. Although this minimally invasive procedure results in less trauma and a reduced hospital stay along with reduced costs then previous prior art procedures, it is still somewhat traumatic since the incision is made through the breast bone.